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Papers by veena chaudhary

The destruction of availability (exergy) during combustion processes is examined for an adiabatic... more The destruction of availability (exergy) during combustion processes is examined for an adiabatic, constant volume system. This is an analytical examination and did not involve experimental measurements. The fraction of the fuel's availability that is destroyed due to the irreversible processes is obtained as a function of temperature, pressure, and equivalence ratio for octane-air mixtures. In general, the destruction of the fuel's available energy due to the combustion process decreases for operation at higher temperatures. In addition, the effect of equivalence ratio on the destruction of availability is significant and depends on the particular operating conditions. Specifically, for the conditions of this study, the destroyed availability due to the combustion process ranged between about 5 and 25% of the original reactant availability. The implications of these results to combustion processes in internal combustion engines are described.

Exergy analysis is a technique at the forefront of applied thermodynamics research whereby system... more Exergy analysis is a technique at the forefront of applied thermodynamics research whereby systems that utilize energy are assessed in the light of the second law of thermodynamics. All forms of energy transfer and transport can be represented by equivalent exergy transfers which are, in fact, the quantities of work that could be producedfrom the same types of energy transfer or transport by perJect thermodynamic devices free to interact with a specijied reference environment. E w g y is conserved and this is a fundamental physical law. Whereas conventional energy analyses can only account for where energy is distributed, or lost @om systems of interest, exergy analysis can highlight where it is used inefficiently. This paper describes and develops the exergy analysis concept. The exergy transfers associated with various types of energy transfer and transport are defned and an 'exergy analysis toolbox' is described. In Part 2 of the paper a universal rational efficiency is described and a number of worked examples are presented to illustrate the application of exergy analysis. Some of the present limitations of the technique and areas for future development are described. * refers to the thermomechanical dead state of the The M S was Downloaded from 254 J A McGOVERN Conventions (dot above symbol) indicates time rate of change of quantity (dot between symbols) indicates the scalar product indicates increase in a quantity A Part

The paper presents an application ofartificial neural network to modelling ofthe processes in Die... more The paper presents an application ofartificial neural network to modelling ofthe processes in Diesel engine cylinder. In our study six independent engine control variables have been identified and used. These parameters determine the engine behaviour (output parameters). In order to found the relations between input and output parameters the radial artificial neural network has been applied. The ANN has been trained on the base of measurement results in order to approximate measurement results of toxicity of exhaust gas components. Measurements data which have been used to training ANN cover a wide range ofsteady state engine operating conditions (more then 230). The ANN modelling accuracy has been controlled by optimisation method which has been used in order to find the influence of given centres of Gauss function.

A computer model is developed for studying the first-and second-law (availability) balances of a ... more A computer model is developed for studying the first-and second-law (availability) balances of a turbocharged diesel engine, operating under transient load conditions. Special attention is paid to the direct comparison between the results from the two laws, for various operating parameters of the engine. The model simulates the transient operation on a degree crank angle basis, using a detailed analysis of mechanical friction, a separate consideration for the processes of each cylinder during a cycle (''multi-cylinder'' model) and a mathematical model of the fuel pump. Experimental data taken from a marine duty, turbocharged diesel engine, located at the authors' laboratory, are used for the evaluation of the model's predictive capabilities. The first-law (e.g., engine speed, fuel pump rack position, engine load, etc.) and second-law (e.g., irreversibilities, heat loss and exhaust gases) terms for the diesel engine cylinder are both computed and depicted in comparison, using detailed diagrams, for various engine operating parameters. It is revealed that, at least for the specific engine type and operation, a thermodynamic, dynamic or design parameter can have a conflicting impact on the engine transient response as regards energy and availability properties, implying that both a first-and second-law optimization is needed for best performance evaluation. r

Conference Presentations by veena chaudhary

This study investigates the effect of various operating conditions in diesel engine via exergy an... more This study investigates the effect of various operating conditions in diesel engine via exergy analysis. The energy (first law) and exergy (second law) analyses for a small single cylinder, water cooled direct injection diesel engine using diesel and biodiesel blends as fuel has been conducted. Both first and second law of thermodynamics are employed to take into account the quality and quantity of energy. Exergy analysis based on the Second law of thermodynamic is utilized to identify the sources of losses in useful energy within diesel engine cycle. The experimental data are collected using steady-state tests which enable accurate measurement of air, fuel, and cooling water flow rates, engine load and all relevant temperatures. Energy and exergy balances are determined for the engine. Exergetic variables, i.e., the exergy transfer with heat and work, irreversibilities, exergy loss accompanying with exhaust gas and exergy destroyed in the engine cycle are calculated and compared with each other. Variation of exergetic parameter are determined for various operating conditions, i.e., engine speed and load. The experimental results of tested biodiesel offer similar energetic performance as petroleum diesel fuel. It is concluded that besides heat transfer, the combustion process is the most important source of irreversibility. It is found that combustion is the dominant irreversibility term.

Books by veena chaudhary

In this study, energy and exergy analyses have been carried out using the experimental data for a... more In this study, energy and exergy analyses have been carried out using the experimental data for a small naturally aspirated, direct injection, single cylinder, 4 stroke diesel engine. The exergy and performance parameters were computed from the measured data. It has been found that significant exergy destruction occurs at low loads. Exergy destruction percentage decreases as the load increases at higher speeds. For low speed and low load conditions the exergy destruction is higher as compared to that at high speed and higher load conditions.